EP 0889005 B1 20011114 - Yttrium oxide-aluminum oxide composite particles and method for the preparation thereof
Title (en)
Yttrium oxide-aluminum oxide composite particles and method for the preparation thereof
Title (de)
Yttriumoxid-Aluminiumoxid Kompositteilchen und Verfahren zu deren Herstellung
Title (fr)
Particules composées de oxyde d'yttrium-oxyde d'aluminium et procédé de préparation
Publication
Application
Priority
JP 17684397 A 19970702
Abstract (en)
[origin: EP0889005A1] Provided by the invention is a powder of alumina-yttria composite particles of which each particle has a structure consisting of a core of alumina and cladding layer of yttria. By virtue of the microscopically intimate and uniform mixing condition of the two oxide components, the powder is useful as a base material of sintered ceramic bodies or as an ingredient in a protective film on fluorescent lamps. The composite particles are prepared by a process comprising the steps of: suspending alumina particles in an aqueous solution containing a water-soluble yttrium salt such as nitrate; dissolving urea in the aqueous suspension; heating the suspension at an elevated temperature to effect hydrolysis of urea into ammonia and carbon dioxide forming a layer of yttrium basic carbonate on the alumina particles; and calcining the basic carbonate-clad particles of alumina at a specified temperature to convert the basic carbonate of yttrium into yttrium oxide.
IPC 1-7
IPC 8 full level
C04B 35/10 (2006.01); C01F 7/021 (2022.01); C01F 17/218 (2020.01); C04B 35/117 (2006.01); C04B 35/505 (2006.01); C04B 35/628 (2006.01)
CPC (source: EP US)
C01F 7/021 (2013.01 - EP US); C01F 17/218 (2020.01 - EP US); C01F 17/34 (2020.01 - EP US); C04B 35/117 (2013.01 - EP US); C04B 35/44 (2013.01 - EP US); C04B 35/62815 (2013.01 - EP US); C04B 35/62886 (2013.01 - EP US); C01P 2004/82 (2013.01 - EP US); C01P 2004/84 (2013.01 - EP US); C01P 2006/12 (2013.01 - EP US); C04B 2235/3217 (2013.01 - EP US); C04B 2235/3225 (2013.01 - EP US); C04B 2235/5409 (2013.01 - EP US); Y10T 428/2991 (2015.01 - EP US); Y10T 428/2993 (2015.01 - EP US); Y10T 428/31504 (2015.04 - EP US)
Designated contracting state (EPC)
DE FR GB NL
DOCDB simple family (publication)
EP 0889005 A1 19990107; EP 0889005 B1 20011114; DE 69802471 D1 20011220; DE 69802471 T2 20020404; JP H1121124 A 19990126; US 6080485 A 20000627
DOCDB simple family (application)
EP 98111936 A 19980627; DE 69802471 T 19980627; JP 17684397 A 19970702; US 10262698 A 19980623